JP2016517361A - Slicing and / or texturing for 3D printing - Google Patents

Abstract

A method for slicing a 3D model to print the corresponding object with a 3D printer, in this case, obtaining the object envelope as a polygon for each region of the predefined work area in the slice plane Identifying the closest polygon of the envelope surface positioned over each of the pixels, marking a corresponding area as a non-print area if no polygon is identified, and a polygon If the nearest direction vector above has a positive component in the Z direction, marking the corresponding region as a model region, and if the polygon direction vector has a negative component in the Z direction, a region Marking as a support area and printing accordingly. The advantage of the above procedure is that slicing and additionally texture mapping can be performed efficiently on the graphics card or GPU.

Description

This application is incorporated by reference in its entirety, and is hereby incorporated by reference in its entirety in US Provisional Patent Application No. 61 / 782,142, filed March 14, 2013, which is incorporated herein by reference. Claim priority interests under e).

  The present invention, in some embodiments thereof, relates to aspects of performing slicing for 3D printing, and more particularly, but not limited to, implemented on a graphics card or graphical processing unit (GPU). It relates to a mode that is particularly suitable for.

  Three-dimensional (3D) inkjet printing, in its broadest sense, is a form of additional fabrication in which any material that can be squeezed through an injection nozzle is deposited in layers according to a plan or model, Form a 3D object.

  The model can be obtained in any one of several ways, for example, by performing a 3D measurement of the original product that is sought to be copied. Alternatively, a 3D design from a computer aided design (CAD) package can be used. As a further alternative, the 3D design can be generated on the fly by the user using a suitable graphics package.

  A 3D model cannot usually be manufactured in its final form. This is because, when injected, each layer melts and usually needs to be at least partially supported during its production. Therefore, a support structure that can be removed later is usually provided. Any print plan for an object should include a print of such a support structure and may incorporate aspects that follow the print to create a support structure that is easily removable.

  In addition, 3D models may require colors and textures, and textures may be simply flat patterns or extend to the depth of the model to some extent for various types of surfaces. It is a feature. Similarly, the support structure may have a texture that is attached to the support structure, particularly at the surface, for example, to allow the support structure to be easily removed.

  The 3D model may further include different materials at different locations. That is, waterproofing may be required around the outer surface, or the soft interior may require a hard outer shell.

  The 3D model needs to be converted into instructions in order to operate the printhead. Typically, the model is cut into slices and then each pixel in each slice is modified by a texture file. Similarly, each individual pixel is tested against the model's envelope surface to determine if the pixel is inside the envelope surface and part of the model, or below the envelope surface and thus part of the support, or Determine if it is outside the envelope and therefore not printed. The pixels are then modified for the texture from a separate texture file. Instructions can then be generated to operate the printer head and print the slice.

  That is, slices are generated for each pixel, and each pixel is stored separately, requiring significant memory. The calculations are typically performed on the central processing unit (CPU) portion of the computer, or customized calculations on the GPU or other graphics hardware can be used, and the customized calculations are complex And very long.

  Graphics processing is commonly available on most computers, typically in the form of a GPU provided in a separate graphics card. Graphics cards are designed with pipelines that are optimized for graphics processing in a manner that bypasses the computation of individual pixels. However, since graphics cards are designed to provide 2D projection of 3D images, graphics cards are not used directly to generate 3D printing instructions from 3D models. 3D processing on graphics cards is typically built with video games in mind to generate 2D projections quickly. 3D imaging requires actual 3D shapes, not projections. For this reason, if a graphics card is to be used for 3D printing, it is only possible via a customized solution.

  This embodiment relates to performing a process of converting a 3D model into print instructions based on identifying and manipulating the volume, rather than calculating and defining individual pixels. Such a process is particularly suitable for being executed on a graphics card, where a projection function can be used to generate a slice, with a specific part of the volume being a part of the support Clipping can be used to determine if it is a part of the model itself or should not be printed.

In accordance with aspects of some embodiments of the present invention, a method is provided for slicing a three-dimensional model for printing a corresponding object by a 3D printer, wherein slicing is performed in a space having a Z axis. The Z axis is perpendicular to the print plane and the method is
Obtaining a representation of an object's envelope as a set of planar polygons, each polygon defined by a shape, position coordinates, and a direction vector perpendicular to each polygon, the direction vector being the object's Facing outwardly, thereby distinguishing the inner surface of the polygon from the outer surface of the polygon;
Defining a slice plane characterized by Z0 coordinates along the Z axis;
Dividing the slice plane into areas within the object, areas belonging to the support structure, and areas outside the object and not to be printed.

In one embodiment, identifying a region in the slice includes
Finding a polygon closest to the envelope surface positioned over each region to be identified;
If the polygon is not identified, marking the corresponding area as a non-printing area;
Marking the corresponding region as a model region if the direction vector of the closest one on the polygon has a positive component in the Z direction;
Marking a region as a support region if the direction vector of the closest one on the polygon has a negative component in the Z direction.

  In one embodiment, obtaining the representation further comprises orienting. One embodiment further includes obtaining a texture map and mapping a region of the texture onto the slice.

  In one embodiment, the texture map includes a map defining a color distribution, a map defining a distribution of various materials, and a map defining a three-dimensional surface texture.

  In one embodiment, each region is a multi-voxel region, and the method further includes defining a voxel in each region of the defined slice region before printing.

One embodiment further includes printing the object in layers, wherein each layer corresponds to a respective slice of a plurality of planar slices, each layer comprising:
Printing by depositing support material on voxels in each region marked as support regions in the respective slices, and depositing model material on voxels in each region marked as model pixels in the respective slices May be.

  In one embodiment, printing a layer immediately follows the corresponding virtual slicing so that the layer is sliced and then printed immediately.

  The method can be performed on a graphics card or a graphics processing unit.

  In a further aspect, the present invention can be extended to a sliced three-dimensional model of an object to be printed, sliced as described herein.

According to yet another aspect of the invention, a method is provided for adding texture to a sliced 3D model for printing a corresponding object by a 3D printer, the method comprising:
Obtaining a representation of the envelope surface of the object as a set of planar polygons;
Slicing the model across the envelope surface;
Obtaining a texture map of the model;
Mapping the texture map onto the slice to generate a defined texture region.

  A further aspect of the invention relates to a sliced and texture mapped 3D model of an object to be printed, sliced and texture mapped using a method as described herein.

  Yet another aspect of the invention relates to a printed three-dimensional object that is printed from a sliced three-dimensional model generated as described herein.

  Yet another aspect of this embodiment is the use of a graphical printing unit (GPU) to slice a three-dimensional model of an object to be printed using any of the methods described herein. About.

  Unless defined otherwise, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used in practice or in testing embodiments of the present invention, exemplary methods and / or materials are described below. The In case of conflict, the patent specification, including regulations, will prevail. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

  Implementation of the method and / or system of embodiments of the invention can include performing or completing selected tasks manually, automatically, or a combination thereof. Further, according to the actual instrument and apparatus of the method and / or system embodiments of the present invention, some selected tasks use the operating system by hardware, by software, by firmware, or a combination thereof. Can be realized.

  For example, the hardware for performing selected tasks according to embodiments of the present invention can be implemented as a chip or a circuit. As software, tasks selected according to embodiments of the present invention can be implemented as a plurality of software instructions that are executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to an exemplary embodiment of a method and / or system as described herein are computing platforms for executing multiple instructions. Implemented by a data processor. Optionally, the data processor comprises a volatile memory for storing instructions and / or data, and / or a non-volatile storage device, such as a magnetic hard disk and / or removable medium, for storing instructions and / or data including. Optionally, a network connection is provided as well. A display and / or a user input device such as a keyboard or mouse is also optionally provided.

  Some embodiments of the invention are described herein by way of example only with reference to the accompanying drawings. Referring now in detail to the drawings in detail, it is emphasized that the details shown are by way of example and are for the purpose of discussion to help explain embodiments of the invention. In this regard, the description using the drawings will make it clear to those skilled in the art how the embodiments of the present invention can be implemented.

2 is a simplified flow diagram illustrating a procedure for slicing a 3D model of an object to be printed according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a 3D model to which the procedure of FIG. 1 is applied. 2 is a simplified flow diagram illustrating a modification of the procedure of FIG. 1 for mapping a texture onto a 3D model.

  The present invention, in some embodiments thereof, relates to an aspect of performing slicing for three-dimensional printing, and more particularly, but not exclusively, to an aspect particularly suitable for execution on a graphics card.

  As will be described in more detail below, a method is provided for slicing a 3D model to print a corresponding object by a 3D printer, which in this case is pre- For each area of the defined work area, acquiring the object's envelope as a polygon, identifying the closest polygon of the envelope positioned above each area, and no polygon is identified Marking the corresponding area as a non-printing area, and marking the corresponding area as a model area if the closest direction vector on the polygon has a positive component in the Z direction; and If the polygon direction vector has a negative component in the Z direction, marking the corresponding region as a support region; Depending on and a step of printing. The advantage of the above procedure is that slicing can be performed efficiently on the graphics card or GPU.

  Before describing at least one embodiment of the present invention in detail, to the details and / or method of arrangement and arrangement of components shown in the following description and / or illustrated in the drawings and / or examples It should be understood that the present invention is not necessarily limited to the application of the present invention. The invention is capable of other embodiments or of being practiced or carried out in various ways.

  Referring now to the drawings, FIG. 1 is a simplified flow diagram illustrating a procedure for realizing slicing of a model prior to printing of an object according to an embodiment of the present invention.

  Embodiments of the present invention use a graphics card viewing frustum, which is a virtual field of view function, to generate a 3D body that is the object to be printed and to divide the object into vertical sections (slices). ). The body is described by a set of polygons in 3D space that define the body surface.

  The fact that this embodiment is a body facing upwards, a surface with a positive normal z component is not seen during vertical projection from the bottom, but can only be seen from the inside of the body Can be used. Similarly, the downward facing surface is seen from the bottom and has a negative normal z component. These planes can be identified by first supplying an orientation vector to the surface that points to the internal body of the model. The orientation vector may be perpendicular to the polygon and may have a component in the z direction.

  To identify such surfaces, all polygonal surfaces with a positive z component of the normal are marked with a color indicating the model material and all polygonal surfaces with a negative z component relative to the normal Are marked with a color indicating the support area.

  A slice may in this case be the result of a vertical projection seen from the bottom, where it can include a model and a support area marked by the color assigned to each.

  As will be explained in more detail below, you can now assign a 3D texture to or around the surface in the slice in the model, where the texture is the desired surface 3D texture, object surface color Provide structures for various object materials, if present, and support areas.

  Features are assigned to the area of the slice and individual pixels are not calculated at this point.

  As a result, the typical slice processing, which would have to calculate thousands of slices and would traditionally take several hours, is performed much faster using the graphics accelerator HW to calculate slices that use vertical projection and clipping Can do.

  More particularly, the slicing method includes generating a vertical section, slice of the 3D body using a frustum of the graphics card. As subsequent slices are generated, the slicer viewpoint is gradually moved in the positive z direction according to the required slice resolution. The viewing frustum is adjusted accordingly.

  Every slice can thus include one or both of the model and the support area, where the area is marked by a different color or pattern assigned to the model surface or a close surface. The color or pattern includes materials, heterogeneous combinations of materials, i.e. digital material (DM) or texture for the support structure.

  Referring again to FIG. 1, as shown in box 100, in the first stage, one or more 3D models are loaded onto the graphics card for off-screen rendering, more precisely MLoad. The model describes an object using a set of polygons that describe the surface of the object to be printed. The model is positioned according to the desired position and orientation.

  Every polygon is part of a 3D surface, which has an inner side and an outer side. In box 102, the normals of any polygon are calculated. In box 104, the z component of the normal is found to mark the inside and outside of the object. Starting at the bottom, all polygon faces with a negative z-normal component are marked with a specific color to indicate the support area, and polygon faces that are positively oriented are marked with the model color Is done.

  Thereafter, as shown in box 106, the position (viewpoint) of the virtual camera is set to z = 0 and begins to define the first slice. The camera position is then incremented for each subsequent slice until the highest model height is reached.

  Then, as in box 108, for each of the slices, as the upward looking virtual camera is slid along the length of the slice, each portion of the slice is projected upward onto the next polygonal plane. If the first polygonal surface in the field of view is the outer surface facing downward, that region of the slice is marked as a support region. If the surface is an inner surface facing downwards, the region is marked as part of the object itself. It will be appreciated that a slice is actually a two-dimensional area, so the process must be performed over the entire area.

  As each slice is completed, the camera or viewpoint is moved up the slice width in the z-direction—box 110.

  The fast parallel computing capabilities of the graphics card can allow slices to be calculated as quickly as above, and as described above, the computation is related to the area of the slice, not individual pixels. Individual 3D pixels or voxels are simply calculated from the properties of the region to which the individual 3D pixels or voxels belong prior to the subsequent printing step.

  Reference is now made to FIG. 2, which is a schematic diagram illustrating how the above procedure can work on an L-shaped model article 200. It will be understood that the model product is a 3D model product, but is shown as 2D for simplicity. The model article has a vertical section 202 and a horizontal section 204, the surface being defined by a polygon, with an inner surface and an outer surface for each surface.

  Now consider the calculation of slice 206. A virtual camera looking upwards is slid along the length of the slice. As long as the virtual camera is in the upright model portion 202, the first surface seen by the virtual camera is the inward facing side of the top wall 208. Accordingly, the area of the slice in the vertical portion 202 is marked as being in the model.

  When the virtual camera exits the upright portion and moves under the L-shaped extension, the first surface that the virtual camera meets is the downwardly facing outer surface of the lower wall 210. Thus, the area outside the upright and below the L extension is marked as a support area.

  In those parts of the slice that are neither inside the model or under the 204 extension, but entirely outside the L shape, the upward looking camera does not encounter the polygonal plane, so the area is a non-printing area Marked as

  According to an embodiment of the present invention, the graphics card can thus render a 3D scene and form a parallel projected view by looking in the Z direction upward from the slice. For each slice, the camera slides upwards from the bottom along a vector in the slice that is set on the z plane of the slice (camera z position) and is perpendicular to the z plane (view direction).

  The graphics card can thus automatically calculate the model and supporting area using polygons, projections, and polygon sorting, ready to later define individual pixels within the area. All visible polygon faces with normal vectors pointing to the inside can be rendered and marked as belonging to the model, and all visible polygons with normal vectors pointing to the outside belong to the support structure Can be rendered and marked.

  In general, it is not sufficient to simply map a region as a model, as a support, or as a non-print. Real-world objects that users need to print require color, different materials in different places, surface patterns, 3D textures, and so on. Again the graphics processor can provide the answer. The texture mapping unit (TMU) is a component in a modern graphics processing unit (GPU). A TMU can rotate and resize a bitmap placed as a texture on any plane of a given 3D object. In modern graphics cards, the TMU is typically implemented as a discrete stage in the graphics pipeline.

  In order to render a 3D scene, the texture is mapped onto the top of the polygon mesh. This is called texture mapping and is accomplished by a TMU on the graphics card.

  The texture map can be attached or mapped to a shape or polygonal surface. The deposition process is close to depositing patterned paper on a flat white box. For example, every vertex in the polygon can be assigned texture coordinates, either through explicit assignment or by procedural definition. Multitexturing is the use of more than one texture at a time on a polygon.

  In embodiments of the present invention, texture mapping as described above is used to generate a target portion of interest or a complex, multi-material structure of a model (e.g., DM) and support, for example, The support can be defined as a grid.

  The method is illustrated in FIG. 3, which is a simplified flow diagram. The method includes using a pre-defined 2D or 3D texture or color map and defining the mapping on the same polygon that defines the model shape. For the slice, one or more texture maps are obtained (box 300). There may be separate texture maps, such as 302 for colors and surface patterns, 304 for various materials, and 306 for various 3D depth textures. Additional texture maps can be designed as needed, and the various texture maps can be combined into one or more files for convenience. In box 308, the texture map region is mapped onto the slice region. Different textures can be attached separately to the sides, outside and inside of two different polygons, and after rendering performed as above, the output includes the color and texture representation of the model or support structure be able to.

  Graphic processors do not have a direct way of representing various materials. However, graphic processors are very good at representing colors, and thus colors can represent different materials in different voxels to be printed in the generated slice. In this way, multitexturing can be used to combine colors that refer to material types with colors that are intended to appear on objects.

  The 3D texture can further be used to generate structures with depth. Since the depth is calculated from the surface, the graphics processor can be coated or layered as part of the projection process to the model depth, and the gradient structure in the direction perpendicular to the surface plane. Can be generated easily. For example, certain objects may require a hard shell and soft filler material on the surface, or may require waterproofing on the surface. A texture map is a way to allow a graphics processor to apply information related to the region in the slice.

  While many related inkjet and other printing technologies are expected to develop during the validity period of the patent from this application, the term “printing” is pre- It is intended to include technology.

  The terms `` comprises '', `` comprising '', `` includes '', `` including '', `` having '' and their inflections are: It means "including but not limited to".

  The term “consisting of” means “including and limited to”.

  As used herein, the singular forms “a”, “an”, and “the” include references to the plural unless the context clearly dictates otherwise.

  For clarity, certain features of the invention described in the context of separate embodiments can also be provided in combination in a single embodiment, and the above description clearly illustrates this combination. It should be understood that it should be interpreted as being. On the contrary, the various features of the invention described in the context of a single embodiment for the sake of brevity are separately or in any suitable subcombination or any other description of the invention. May be provided as preferred in the described embodiments, and the above description should be construed as if these separate embodiments were explicitly written. Certain features described in the context of various embodiments should not be considered essential features of those embodiments, unless the embodiment is inoperable without those elements.

  While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

  All publications, patents, and patent applications mentioned in this specification are specifically and individually indicated when each individual publication, patent, or patent application is incorporated herein by reference. To the same extent, are hereby incorporated by reference in their entirety. In addition, citation and identification information of any reference in this application should not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not necessarily be construed as limiting.

200 L-shaped model
202 Vertical section, vertical section
204 Horizontal section
206 slices
208 Upper wall
210 Bottom wall

Claims (14)

A method for slicing a three-dimensional model to print a corresponding object by a 3D printer, wherein the slicing is done in a space having a Z axis, the Z axis being perpendicular to the print plane, The method comprises
Obtaining a representation of an object's envelope as a set of planar polygons, each polygon defined by a shape, position coordinates, and a direction vector perpendicular to each polygon, the direction vector being the object's Facing outwardly, thereby distinguishing the inner surface of the polygon from the outer surface of the polygon;
Defining a slice plane characterized by Z0 coordinates along the Z axis;
Dividing the slice plane into regions within the object, regions belonging to a support structure, and regions that are outside the object and are not printed. Identifying an area within the slice;
Finding the closest polygon of the envelope located above each region to be identified;
If the polygon is not identified, marking the corresponding area as a non-printing area;
Marking the corresponding region as a model region if the direction vector of the closest one on the polygon has a positive component in the Z direction;
And marking the region as a support region if the direction vector of the closest one on the polygon has a negative component in the Z direction.   The method of claim 1, wherein obtaining the representation further comprises orienting.   4. The method according to any one of claims 1, 2, and 3, further comprising obtaining a texture map and mapping a region of a texture on the slice.   5. The method of claim 4, wherein the texture map includes a map defining a color distribution, a map defining a distribution of various materials, and a map defining a three-dimensional surface texture.   6. Each region is a multi-voxel region, and the method further comprises defining a voxel in each region of the defined slice region before printing. the method of. Printing the object in layers, each layer corresponding to a respective slice of a plurality of planar slices, each layer comprising:
Printing by depositing support material on voxels in each region marked as a support region in the respective slice, and depositing model material on voxels in each region marked as a model pixel in the respective slice 7. The method according to any one of claims 1 to 6, wherein:   8. A method according to any one of the preceding claims, wherein printing a layer follows immediately after the corresponding virtual slicing.   9. The method according to any one of claims 1 to 8, wherein the method is executed on a graphics card or a graphics processing unit.   A sliced three-dimensional model of an object to be printed, sliced using the method according to any one of the preceding claims. A method for adding texture to a sliced 3D model to print a corresponding object with a 3D printer,
Obtaining a representation of the envelope surface of the object as a set of planar polygons;
Slicing a model across the envelope surface;
Obtaining a texture map of the model;
Mapping the texture map onto the slice to generate a defined texture region.   A sliced and texture mapped three-dimensional model of an object to be printed, sliced and texture mapped using the method according to any one of claims 1-8.   A printed three-dimensional object printed from a sliced three-dimensional model generated according to any one of claims 1-8.   Use of a graphical printing unit (GPU) for slicing a three-dimensional model of an object to be printed according to any one of claims 1-8.

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